cast-iron

a cast-iron promise or arrangement is one that can be trusted completely (always before noun) No new business comes with a cast-iron guarantee of success.

Common Names:

Name	Pronounced	Usage
Mercia	-	English (Rare)
Hilarius	-	Ancient Roman
Aesop	EE-sahp (English)	Ancient Greek (Anglicized)
Elysia	-	Various
LĖJa	-	Lithuanian
Herleif	-	Norwegian